CURRENT STATE OF SOLID WASTE LANDFILL MANAGEMENT AND HEAVY RAIN IMPACTS ON LEACHATE: CASE STUDY IN VIETNAM

Abstract

 This study is the first effort to depict the situation of solid waste landfill management in Vietnam. A comprehensive-nationwide-survey was conducted at 13 Vietnamese landfill sites in 2018 to clarify problems of landfill sites under impacts of heavy rain. The survey started with an overview of the landfill management situation along with investigation of the potential contamination of landfill leachate by computing the leachate pollution index (LPI). As a result, owing to the inadequate management of the facilities and high LPI value, the occurrence of heavy rain potentially induces the overload of leachate through its infiltration into landfill body leading it to pose risks to environment. Additionally, the actual incidents caused by heavy rain and the existing strategy to tackle the problems were reported. Based on this, we proposed suggestions to contribute to dealing with heavy rain events ahead. Landfill No. 8 with high leachate monitoring frequency system, provided 5-year leachate monitoring data (2013-2017). Statistical analysis applied on this data set showed a significant relationship between cumulative rainfall and leachate component concentration. The 2013-2015 period showed a negative correlation between rainfall and COD concentration, whereas the 2016-2017 period depicted a positive correlation between them. This can be explained by the starting of a new cell in the landfill to accept wastes in the 2016-2017 period. The remaining leachate components (BOD₅, TN, NH⁴⁺_-N, and Cl^-) had weaker correlation with rainfall compared to COD. Welch t-test was used to further investigate the impacts of heavy rain intensities on leachate component concentration. Results indicated that the impact of heavy rain intensity on COD, Cl^- (2013-2015) and COD, BOD₅ (2016-2017) has statistical significance.